The Control is nice and works as indicated. I guess the thing I see which would need to be improved upon, is that if you have sub categories it ignores them and doesn't list them. For example. The Root Category would be set to Dog. The category under dog would be listed correctly, ex. Labrador Retriever. If there is another category under Labrador Retriever such as Black, Yellow, Brown, etc. Those additional categories are excluded.
Additionally, it lays out everything in a vertical layout. Flow would be better since those with a lot of categories would have a long page.
Finally, it is a great Form Control, and I like the fact that you can set it to start at a specific Parent Category.